ESTRO 2025 - Abstract Book

S1798

Clinical – Upper GI

ESTRO 2025

Figure 1: survival outcomes of chemoradiation compared to chemotherapy alone

Conclusion: CRT seems an effective alternative to standard CHT. The meta-analysis confirmed a significant advantage of concurrent CRT in terms of OS, but more trials are needed to strengthen this result.

Keywords: Unresectable Biliary Tract Cancers

2454

Digital Poster Robotic stereotactic body radiotherapy for malignant liver lesions: Local control and overall survival – a Monoinstitutional study. Ahmed Abdelmaqsoud, Mariam Zurabashvili, Omar Habibeh, Georgios Skazikis, Stephan Mose Radiation Oncology, Schwarzwald-Baar Klinikum, Villingen-Schwenningen, Germany Purpose/Objective: Local treatment options for malignant liver lesions include surgery, radiofrequency ablation, and transarterial chemoembolization. In recent decades, radiotherapy has become a valuable treatment alternative. This study aims to evaluate the treatment outcomes of patients with various hepatic tumor entities treated with the CyberKnife. Material/Methods: All patients treated with robotic SBRT for malignant liver lesions between 01/2016 and 01/2023 were analyzed for demographics and tumor characteristics. Data included age, sex, primary diagnosis, liver segments, lesion size, number and treatment protocol. Local control (LC) and overall survival (OS) at 1, 2, and 3 years were analysed. Results: In total all 41 patients (75.6% male, 24.4% female), with a median age of 71 years (45–86) were included. Primary diagnoses included hepatocellular carcinoma (HCC) (48.8%), cholangiocarcinoma (9.8%), and metastatic lesions (41.5%). Number of lesions were 1-5 (total 59) and the sizes ranged between (0.8 - 6.5 cm). Most commonly applied protocols were 5 x 10 Gy and 3 x 17 Gy, (range: 3-12 fractions). Mean PTV was 62.2 cm³ (3.3–205 cm³). 61% of patients had prior treatments. The mean total radiotherapy dose was 50.5 Gy (35-66 Gy), with a mean single dose of 12.8 Gy (5–18 Gy). The BED with α/β ratio of 10 was 115 Gy (59.5–152.2 Gy). The LC rates were 61.1% at 1 year, 43.8% at 2 years, and 37.9% at 3 years. OS rates at 1, 2, and 3 years were 92.5%, 88.9%, and 69.0%, respectively. The mean time to progression was 14.1 months (2–49). The mean follow-up was 32.6 months (0–86). 34.4% of the patients experienced mild acute toxicities, grade 1 or 2 only. No late toxicities were observed. There was no significant difference in LC based on BED, more or less than 120 Gy. HCC and Child-Pugh A status demonstrated better OS at 2 and 3 years. For hepatobiliary tumors, LC was better for lesions with PTV ≤ 40 cm³.